Nano-engineered catalysts for high-performance oxygen reduction reaction

The efficient energy conversion of fuel cells is greatly constrained by the slow oxygen reduction reac tion （ORR） kinetics,which necessitates the use of highly active metal catalysts such as platinum （Pt）.The critical challenge limiting large-scale usage of Pt is the capital cost that can be addressed through a pro totypical approach by embedding metal nanoparticles （NPs）,e.g.,Pt NPs,in the conductive framework However,previously reported embedding approaches are sophisticated and suffer from limited yields leading to higher chemical process costs and remaining distant from commercial viability.Here,we re port a facile,cost-effective and time-efficient structural tuning approach to synthesizing ultrafine Pt NP impregnated within a conductive and highly porous carbon framework via a microwave-assisted polyo reduction method.Pt NPs with a uniform size of～2.27 nm can be successfully integrated within the pore of the carbon framework,enabling homogeneous dispersion.Benefiting from these highly dispersed and ultrafine Pt NPs,the electrochemical surface area （ECSA） is improved to 142.98 m2/gPt,2.25 times highe than that of the commercial counterpart (63.52 m2/gPt).Furthermore,our structurally optimized catalys composite features a remarkably catalytic activity with a high half-wave potential (E1/2) of 0.895 V and an improved mass activity （MA） of 0.2289 A/mgPt,2.39-fold improvement compared to the commercia counterpart.In addition,orthogonal experiments were designed to identify the key process parameter for fabricating Pt/C catalysts,offering insights for scaled-up and industrial production.